Method of operating on thermoplastic eyelets



March 14, 1944.

c. D. KNOWLTON METHOD OF OPERATING ON THERMOPLASTIC EYELETS I Dec. 8, 1941 I '3. Fig: 4. Q

atented an". 1 9 1944 METHOD OF OPERATING N THERMO- PLASTIC EYELETS Cutler D. Knowlton, Rockport, Mass., assignor to United Shoe Machinery Corporation, Flemington, N. J., a corporation of New Jersey 4 Original application December 8, 1941, Serial No. 422,136. Divided and this application April 29, 1943, Serial No. 484,995

7 Claims. (C1. 218-29) This invention provides a novel method of operating on thermoplastic eyelets and is herein set forth with reference to setting such eyelets in shoe uppers. This application is a division of my copending application for United States Letters Patent Serial No. 422,136, filed December 8, 1941.

' The technique evolved to practice this method comprises the step of heating the entering end of an eyelet without upsetting it and without heating the opposite end, and thereafter upsetting, and at the same time cooling the heated end. The portion of an eyelet barrel that ex.- tends beyond the eyelet-receiving material to be transformed into a revolute clenching flange is: the only portion that requires softening to satisfy the needs of this method. Consequently, a nonheated tool or anvil in contact with the head of the eyelet will prevent softening that end while the entering end is being softened by heat from a heated element. No upsetting pressure is applied during the heating stage, but, once the entering end has been softened, the eyelet and the heated element are separated and endwise upsetting pressure is applied as promptly as possible to the eyelet by two cooperative non-heated elements one of which may be the anvil used in the heating stage.

While the softened end of the eyelet is being transformed by the non-heated upsetting tool. it becomes cooled thereby and its normal hardness nearly, if not entirely, restored before the upsetting pressure is removed Moreover, since the heat applied to the eyelet is localized atthe entering end, the intermediate portion of the barrel will remain capable of withstandingthe upsetting pressure without beingcollapsed.

Referring to the drawing,

Fig. 1 is a perspective view of a quarter of a shoe upper into which thermoplastic eyelets have been inserted in readiness for softening and clenching;

Fig. 2 represents a longitudinal section of a thermoplastic eyelet in which the heated and non-heated portions are indicated by dissimilar shading;

Fig. 3 is an elevation of portions of a machine for operating on eyelets according to the method herein set forth:

Fig. 4 is a sectional view of the elements used in the heating stage of method; and

Fig. 5 is a sectional View of the elements used in the upsetting and cooling stage.

The left quarter of a shoe upper is represented in Fig. I, the leathpr'lining 65 being above the cuter leather 66, an eyelet stay d'f' being located between them, and a row of thermoplastic eye lets being, inserted into closely fitting holes previously punched through the three layers above: named. The heads 68 of the eyelets lie against the layer 66.. while the entering ends 69 of the barrels project above the lining.

In Figs. 4 and 5 the eyelet-receiving material is represented as one thick layer 66 instead of three thin layers to avoid confusing lines that. would obscure surface indentations. The holes punched for the reception of theeyelets are preferably a little smaller than the barrels to insure retension of the eyelets by friction. When the head 68- of an eyelet is pressed home against one s rfaceof the work the entering end 69 will project from the opposite surface. I The head '68 may be placed on a non-heated anvil l0 provided with a centering pin 32 adapted to fill the barrel of the eyelet. This pin is normally raised as in Fig. 3' by a compression spring 34.

A presser foot may beused to press the eyeletreceiving material against a supporting surface 6| of the base 30 in. which the anvil is fixed.

Once the work is located and secured on the anvil, the next step is to soften the entering end of the eyelet with heat. This may be done without damaging the eyelet-receiving material by depressing an electrically heated tool H to the position represented in Fig. 4. The lower end of this tool is a narrow circular head 21 intended to impress a groove in the upper surface of the eyelet-receiving material. The bore of the tool II is but little greater than the outside diameter of the entering end of an eyelet. Moreover, a pin 24 in the center of this tool projects a short distance below the bead-21 and is rounded to enter an eyelet without upsetting it, but is of a size to engage the internal surface of thebarrel. These details render the pin 24 effective to center the entering end of an eyelet and guide it into the annular heating chamber 25 where an inter-' val of about one second is enough to soften it.

As the pin 2t descendsinside the eyelet it detion of the eyelet. In Fig. 2 the softened portion is represented by dark shading between the lines raise it to clear the eyelet, move it laterally, shift the non-heated upsetting tool l2 into alignment with the anvil, and depress the tool I2 to the position represented in Fig. 5. The central pilot 4| of this tool will enter the eyelet, but the annular upsetting surface 40 of concave section will- I transform the entering end of the eyelet while it is still soft. The soft portion. of =theeyel'et will be transformed into a revolute clenching flange by the tool l2 and its rim will be embedded in the annular groove previouslyimp'resse'd into the 4 eyelet-receiving material by' thebead 27. "The" tool l2 will also reduce the temperature of the clenched portion and restoreit to a hard condi-.-=

tion. While the clenching pressure is being applied by the tools I ii and 'l2 the pilot 4| will brace thebarrel of the eyelet against its tendency to be collapsed and will preserve its true shape and diameter, An interval of about one second of contact of the tool l2 with-the eyelet'is suflicientto performv the transforming operation and restore the transformedportion to a 'hard or rigid state. Finally, the operator may retract the tool l2, raise the 'presser foot 60, remove the work, pull the locking pin' '35 to release the centeringpin 32, and place another eyelet on the anvil.

Referring to Fig.3, the heated tool I I is aflixed to a block l5 of copper or bronze in which an electric heating unit I3 is embedded. This block is carried by a movable head but is thermally insulated therefrom. The non-heated tool 12 is also carried by the head but is insulated from the block l5 to remain at or near room temperature while the tool H is maintained'at a temperature about 300 F.

Having thus described my invention, what I on thermoplastic eyelets which consists in inserting one end of the barrel of an eyelet through and beyond a closely fitting hole in a work-piece, softening that end of the barrel with heat, forming a depression in the adjacent surface of the work-piece, separating the eyelet and the source of heat, and thereafter transforming that end of the barrel into a revolute flange with pressure by which a portion of such flange is embedded in said depression.

: l 4. That improvement in methods of operating on thermoplastic eyelets which consists in inserting one end of the barrel of an eyelet through claim as new. and desire to secure by Letters Pat ent of the United States is:

1. The method of setting a thermoplastic eyelet which consists in thrusting the barrel thereof through and beyond a hole in a work-piece whilethe eyelet is unheated, softening the projecting entering endof the barrel with heat without softening the Opposite end thereof, separating the eyelet and the source of heat, and thereafter upsetting the softened end against the work-piece and simultaneously cooling it.

2. That improvement in methods of operating on thermoplastic eyelets which consists in inserting one end of the barrel of an eyelet through and beyond a closely fitting hole in a work-piece,

without softening the opposite end of the barrel, separating the eyelet and the source of heat, and thereafter simultaneously upsetting and cooling the heated end of the barrel.

3. That improvement in methods of operating softening that end of the barrel with heat but I andibeyond a tightly fitting hole in a work-piece,

simultaneously softening that end of the barrel with heat and impressing an encircling groove in the-adjacent surface of the workpiece, maintaining the opposite end of the barrelin a hard condition-while the end first mentioned is being softened with heat, separating the eyelet and the source of heat, and transforming the softened end into a revolute-flangewi-th pressure by which the rim of such flange is embedded in said groove.

5. That improvement in methods ofoperating on thermoplastic eyelets which consists in inserting one 'en'd'of the barrel of an eyelet through and beyond a closely fitting hole in a work-piece, softening that end of the barrelwithheat transferred to it both-internally and externally, separating the eyelet, and the source of heat, and transforming that end of the barrel into a flange with pressure of .a cooling instrumentality.

6. That improvement in methods of operating on-thermoplastic eyelets each having a barrel to be transformed at one end and a head at the opposite end, which consists in inserting the end first mentioned through and beyond a closely fitting hole in a work-piece, softening that end with heat while maintaining said head in a hard condition, separating the eyelet and the source of heat, and simultaneously transforming the softened end into a flange and cooling it by contact with a transforming instrumentality at or near room temperature.

'7, That improvement in methods of providing a work-piece with a thermoplastic eyelet which consists in punching a hole in the work-piece. thrusting the entering end of a tightly fitting single-flange eyelet through and beyond the punched hole in the work-piece, 'softening the entering end of the eyelet by contact thereof with a heated element and at the same time maintaining the flange of the eyelet in contact with a nonheated metallic element, separating the entering end of the eyelet and the heated element to arrest the softening effect of the latter, and upsetting the entering end of the eyelet while yet soft with heat derived from said heated element by subjecting the eyelet to endwise pressure by two nonheated eyelet-engaging elements.

CUTLER D. KNOWLTON. 

